What is it?

A 2013 Panamera S with a new bi-turbo 3.0-litre V6 where the 4.8-litre V8 used to be. Porsche has deemed the old engine too inefficient to continue in any model below the GTS, and has downsized accordingly.

It likes to describe the V6 as a cut-down version of its predecessor, but realistically the new motor is a heavily fettled (and slightly smaller) variant of the naturally aspirated 3.6-litre six-pot that already underpinned the range.

Don’t let that put you off though, because this is another forced-induction, belt-tightening affair that easily eclipses the raw figures of its forerunner.

With two turbochargers running at up to 1.2 bar, a new fuel-injection system and variable valve timing on both the intake and exhaust side (the latter being a first in a V engine from Porsche), power surges to 414bhp. That's 109bhp more than the V6, and even 20bhp more than the old V8 managed.

Even better from a Gran Turismo point of view, peak twist now levels out at 383lb ft. That’s as much as you’ll get from the V8 in its current GTS guise, and from 1750rpm earlier. It’s only 22lb ft back from the oil-burning V6 Porsche still sources from Audi.

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And while it obviously can’t match that diesel engine’s economy, the bi-turbo - in this, the rear-wheel-driven Panamera - does deliver a respectable 32.5mpg via the now standard seven-speed PDK (sadly, the six-speed manual is no more).

What's it like?

Fast, scarily flexible, refined and only a tiny bit underwhelming. The rousing brutishness of the old V8 has been replaced by an engine that feels impeccably well honed for the job at hand.

At low speeds, where its predecessor once dilly-dallied under measured throttle inputs, the V6 sweeps forward encouragingly — even when left in its default mode rather than ramped up by the Sport button.

Lag is all but imperceptible and the revised PDK (which now includes virtual gearing - a way of finely reducing engine speeds by engaging an adjacent ratio and then slipping its dual clutches rather opting for an outright ratio change) is swifter and slicker than ever.

The motorway experience, is, if anything, even more impressive. Porsche, concerned about the inherent difference in smoothness between the six- and eight-cylinder engines, has installed a balancer shaft above the crank, quelling the natural imbalance to brilliant effect.

Taken together with efforts made to recalibrate and remount the Panamera’s suspension for a more pliant ride, the result is a truly superior, cross-continent GT car.

It barely misses a beat away from the autobahn, either. The flatter 90-degree cylinder bank angle keeps the centre of gravity low, and its mounted further back towards the middle of the car than the V8 was - and it’s also lighter.

Left to power just the rear wheels, the V6 makes the uncannily well-balanced S feel like it's got a real fire in its belly; directly powering a change of direction which is about as sharp as it's possible to get in a five-metre-long, 1810kg four-seater.

Ironically, it’s by exploiting the new Panamera’s authority and extraordinary stability that the occasional eight-pot pang crops up. The bi-turbo, for all its polish and answer-for-everything retort, doesn’t quite have the high-rev punch or the braggadocio of the old V8.

It revs cleanly into an enjoyable low growl - helped along by the same diaphragm used in the GTS to transmit induction noise into the cabin - but can’t replicate the 7100rpm of authentic, old-world chatter that made the previous car such a memorable steer.

Should I buy one?

Probably. The bi-turbo’s faults - such as they are - are largely subjective and even then they only take an upper most layer of sheen off what is an extremely credible package.

If, for you, the Panamera is all about squashing unthinkably long autobahn drives into snug, subsonic jaunts (with a technical alpine pass to finish) then the V6 has made a better GT of Porsche’s limo.

If, however, you think of the four-door pimple as a wheeled anvil - engineered to have unforgettable smash and grab commutes hammered into it, then there are several notable eight-cylinder rivals lurking at the £82,079 mark. A BMW M5 would be £10k cheaper and nearly a second faster to 62mph.

The soon-to-be-launched Audi RS7 should be even quicker. Or you could add £10k and get the full-on GTS model, which remains the Panamera to boast about.

Two things though. Firstly, I thought they all had rear spoilers that came up at speed? This looks like a plain hatch. Second, I see it has the same magic eye radar thing in the lower grill as most MK7 Golf's have these days

Porsche knows how to do the interiors. Sumptuous. The question is why shouldn't I buy a Cayenne instead? No wonder I don't see many Panameras on our roads. Americans and Chinese however love posh saloons and they have the cash too.

Porsche panamera is morphing into such a trend setter in this class of motoring. Its been derided by hoards of straight jackets for all these years since porsche gifted it to the non-adventurous conformists of this planet.......and it has sold by the dicken tonnes. That should be a statement enough to anyone doubting motor vehicle pedigree from stuttgart!!!